1. Field of the Invention
This invention relates generally to electronic image generation. In particular, it relates to a dotmatrix image formation method in which light is passed through each of a plurality of pixel light gates which are controlled according to imaging data and are caused to have an intensity distribution.
2. Description of the Background Art
There is well known a dot-matrix image forming method for forming a pictorial image on a photo-sensitive material by using dots that are controlled according to pictorial data, usually in the form of electrical signals. This method may be practiced by using, for instance, an image forming device which is manufactured by HELL Co. and sold under the trademark "CHROMACOM".
In the method, a laser beam is used to form dots different in size on the photo-sensitive material, thereby to form a dot-matrix picture having finely distributed gradation.
The method is extensively employed, because it is advantageous over the method of reproduction photography of forming dot-matrix images by using, for instance a contact screen. The advantages lie in the fact that the photo-sensitive material can be readily handled, pictures and characters can be readily edited by controlling the electrical signals, electrical signals can be readily and satisfactorily corrected by a machine operator while corresponding operations on the completed picture would be virtually impossible for a technician to accomplish. An example of such a correction would be improving the saturation of an exposed picture.
Japanese Patent Application (OPI) No. 98073/1981 has disclosed an apparatus in which a liquid crystal light gate is disposed between a light source and an "ElectroFax" sheet and is driven by electrical signals to perform the printing operation.
Owing to the rapid progress of electronics, the control section of an apparatus for practicing the abovedescribed method of forming dot-matrix pictures by using a laser beam can be manufactured at low cost. However, the apparatus is still expensive as a whole because the optical system and its laser beam scanner have a considerably high manufacturing cost. Furthermore, since the scanner is intricate in construction, the maintenance of the apparatus is rather troublesome. Accordingly, the apparatus is used only in large central facilities and wide use of the apparatus cannot be expected at the present.
The printing apparatus with a liquid crystal light gate, as disclosed by Japanese Patent Application (OPI) No. 98073/1981, is intended for a copying operation, and cannot form pictures rich in gradation.